Battle of Monte Circeo

The Battle of Monte Circeo (August 1503) was a battle of the Italian War of 1499-1504 that occurred when a few escaped Venetian mercenaries commandeered a prototype tank at the Papal fortress of Monte Circeo and destroyed the three other prototypes of the tank, which were employed by the Papal Army. The battle prevented Cesare Borgia from using these tanks as the centerpiece for a surprise assault on Sicily.

History
In August 1503, Ezio Auditore da Firenze assassinated the overseer Pardo D'Alesio and discovered that Leonardo da Vinci's prototype tank was being stored at Monte Circeo, located 100 miles from Rome. Auditore arrived in the Borgia-occupied settlement and managed to track down the engineer, Patroclo de Biase, and he forced him to give up the location of the tank plans, the location of the device, and a tutorial on how to use the tank. Auditore headed to the opposite end of the fortress and burnt the plans for the tank, and he then freed three Venetian captives from their prison cell. The Venetian troops informed Auditore that Borgia intended the tank as the centerpiece of his forces, and that his army was preparing for a surprise assault on Sicily. Auditore and the mercenaries fought their way past Papal troops and commandeered one of the tanks, piloting it down a nearby valley. They used the tank to blast fleeing Papal troops, to destroy Borgia cannon, and to blast open the gates of the main factory. The commandeered tank destroyed a tank outside of the fortress before destroying two more inside of the factory, and it also destroyed several damaged siege towers and cannons, crippling Cesare's army. The mercenaries took their leave and fled, and Auditore climbed to one of the buttresses of the tower, using a mounted cannon to destroy the tank before leaving. Borgia's army was now left without its powerful tanks, and it was also deprived of several men and siege equipment, preventing it from invading Sicily.